test(wallet): small cleanups to test_wallet_transactions_relevant #1421

Job	Run time
prepare	3s
Check no_std	32s
Build and test (1.83.0, true, --no-default-features --features miniscript/no-std)	2m 13s
Check WASM	48s
Build & Test Examples (example_cli)	28s
Build and test (1.83.0, true, --all-features)	4m 3s
clippy_check	1m 9s
Build and test (1.63.0, --no-default-features --features miniscript/no-std)	3m 55s
Build & Test Examples (example_bitcoind_rpc_polling)	37s
Rust fmt	11s
Build and test (1.63.0, --all-features)	6m 5s
Build & Test Examples (example_electrum)	52s
Build & Test Examples (example_esplora)	53s
Build & Test Examples (example_wallet_electrum)	57s
Build & Test Examples (example_wallet_esplora_async)	58s
Build & Test Examples (example_wallet_esplora_blocking)	59s
Build & Test Examples (example_wallet_rpc)	39s
	25m 22s

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